While on LOA I'm been layoff.The company wants to relocate me to another lower paying job, Because of all the unfarenness in my team, me been the only one after 11 yrs been laidoff. I just want to take the "Lump sum" and go. But i'm afraid they(HR) will some how mess with me and try not to pay, can they do any thing like this???

Your post is very disjointed and I'm not sure I understand the situation, but is this right?

You are on a leave of absence. Is the leave FMLA-qualifying?

I was put on Medical leave in June08 because I take ambien to go to sleep. My Dr. made me a note stating I can’t drive or answer the phone after I take this on my own time. The company put me on medical leave for a year or when I stop taking this med. They paid me for 6 weeks only. Now they send me 60 day lay off notice. In my team and my kind of work I was the only one laid off. I have been with this co. for 11 yrs. 3 yrs ago I won judgment from the EEOOc for retaliation and harassment. No one else in my field was laid off.
HR called me asking me to take a lower paying job in another part of the company. Because of all the previous problems with them, and seen how they don’t change. I want to take the lump sum layoff benefit, but because I don't trust them to do the right thing, I’m afraid HR will somehow denied me the money. And if I sign the paper I will sign away my rights, I have to decide by February 22. Can you please advise me on what to do?? I don’t want to go back. Thank you

You have been off work WAY longer than any job protection law (specifically, FMLA) provides for.

I cannot advise you "what to do". I can recommend, however, that you take the agreement to a local attorney versed in contract/employment law, who can tell you what your options are.